How much they are worth depends very much on the quality of each fleece, how well they have been stored and how well prepared they are. There is a bit on my website about assessing a fleece which might be helpful.
Handshorn fleeces are usually better for working with as they are cut through the rise, whereas machine fleeces may have been shorn closer to the skin and include some of the new growth - this forms very annoying noils on processing.
For a first shear, clean, uncotted, skirted and well presented fleece, your neighbour could ask up to £10 each. She is better not to sell poor quality fleeces as they simply refect badly on the seller and your customers don't come back the next year.
I think it very important not to sell fleeces too cheaply - the message you are sending is that they are relatively worthless whereas in fact wool in all its forms is a magical product which will come back into its own soon, with rising oil prices (oil is used in the manufacture of most man-made fibres, it is used to make fertilisers for growing cotton, and to power processing machinery and transport. Wool is renewable as a sort of by-product of meat production, and needs very low oil inputs in its production and processing. In addition, wearing woollen clothing, using wool around the house in bedding and carpets, reduces the amount of oil needed for heating)